import {
  AndRule,
  type DataRef,
  LiteralRule,
  MaybeRule,
  type Rule,
  type RuleTestResponse,
} from '@os-team/lexical-rules';
import type { Parser } from './Parser.js';
import ExternalIDParser, { type ExternalID } from './ExternalIDParser.js';
import IntSubsetParser, { type IntSubset } from './IntSubsetParser.js';
import SRule from '../rules/SRule.js';
import NameRule from '../rules/NameRule.js';

export interface DoctypeDecl {
  name: string;
  externalID?: ExternalID;
  intSubset?: IntSubset;
}

/**
 * The document type definition.
 * See https://www.w3.org/TR/xml/#NT-doctypedecl
 */
class DoctypeDeclParser implements Parser<DoctypeDecl> {
  private readonly externalIDParser: ExternalIDParser;

  private readonly intSubsetParser: IntSubsetParser;

  private readonly rule: Rule<
    [
      string,
      undefined,
      string,
      [undefined, ExternalID] | undefined,
      undefined,
      [string, IntSubset, string, undefined] | undefined,
      string,
    ]
  >;

  public constructor() {
    const prefixRule = new LiteralRule('<!DOCTYPE'); // '<!DOCTYPE'
    const sRule = new SRule('+'); // S
    const nameRule = new NameRule(); // Name
    this.externalIDParser = new ExternalIDParser(); // ExternalID
    const sAndExternalIDRule = new AndRule([sRule, this.externalIDParser]); // S ExternalID
    const maybeSAndExternalIDRule = new MaybeRule(sAndExternalIDRule); // (S ExternalID)?
    const anySRule = new SRule('*'); // S?
    const openingSquareBracket = new LiteralRule('['); // '['
    this.intSubsetParser = new IntSubsetParser(); // intSubset
    const closingSquareBracket = new LiteralRule(']'); // ']'
    const intSubsetInBrackets = new AndRule([
      openingSquareBracket,
      this.intSubsetParser,
      closingSquareBracket,
      anySRule,
    ]); // '[' intSubset ']' S?
    const maybeIntSubsetInBrackets = new MaybeRule(intSubsetInBrackets); // ('[' intSubset ']' S?)?
    const suffixRule = new LiteralRule('>'); // '>'
    this.rule = new AndRule([
      prefixRule,
      sRule,
      nameRule,
      maybeSAndExternalIDRule,
      anySRule,
      maybeIntSubsetInBrackets,
      suffixRule,
    ]); // '<!DOCTYPE' S Name (S ExternalID)? S? ('[' intSubset ']' S?)? '>'
  }

  public test(ref: DataRef, pos: number): RuleTestResponse<DoctypeDecl> {
    const [isValid, nextPos, res] = this.rule.test(ref, pos);
    if (!isValid || res === undefined) return [false, nextPos];

    const [, , name, rawExternalID, , rawIntSubset] = res;
    const [, externalID] = rawExternalID || [];
    const [, intSubset] = rawIntSubset || [];
    const doctypeDecl: DoctypeDecl = { name };
    if (rawExternalID) doctypeDecl.externalID = externalID;
    if (rawIntSubset) doctypeDecl.intSubset = intSubset;

    return [true, nextPos, doctypeDecl];
  }

  public build(data: DoctypeDecl) {
    const externalID = data.externalID
      ? ` ${this.externalIDParser.build(data.externalID)}`
      : '';
    const intSubset = data.intSubset
      ? ` [${this.intSubsetParser.build(data.intSubset)}]`
      : '';
    return `<!DOCTYPE ${data.name}${externalID}${intSubset}>`;
  }
}

export default DoctypeDeclParser;